


New Game

by Aialize



Category: Assassination Classroom, Katekyou Hitman Reborn!
Genre: Cross-Posted on FanFiction.Net, Crossover, Gen, Gen Work
Language: English
Status: In-Progress
Published: 2018-09-27
Updated: 2018-09-27
Packaged: 2019-07-18 04:51:56
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 3,900
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16111190
Author URL: https://archiveofourown.org/users/Aialize/pseuds/Aialize
Summary: There was a new hot target in town: a yellow octopus that could reach Mach 20. Of course, being the strongest Famiglia, Vongola got wind of this and decides to send one of theirs. But one Famiglia sent theirs as well. It's Vongola against Shimon for the 10 billion yen. But they better not forget about other assassins and hitmen, as well as class 3-E. Gen.





	1. Target 1: Money

**Summary for the Chapter:**

> In which Vongola and Shimon nake a move for ten billion yen.

**Notes for the Chapter:**

> DISCLAIMER: I do not own Katekyo Hitman Reborn and Assassination Classroom

Glare.

Glare.

 _Burn_.

"Even if you glare at the paperwork, they won't go away Dame-Tsuna."

Tsuna huffed as he looked into the eyes of Reborn, who was currently sitting on his office desk while sipping a mug of coffee. It was odd seeing the self-proclaimed (but had the credibility to back it) World's Greatest Hitman — also known as the Sadistic Tutor from Hell — so relaxed and satisfied.

Tsuna brought his eyes back to the stack of papers and folders in front of him. Maybe he could burn it?

"No."

"I swear Reborn, it feels like you're the one with the Hyper Intuition, not me."

"You're just easy to read, Dame-Tsuna. Anyway," Rebron sipped his coffee, "have you picked out a proper candidate? Nono is expecting the answer soon."

The reluctant Decimo looked at Reborn, frowning. Despite all of his complaints and efforts, in the end, he did become Vongola Decimo because he knew he was already too deep in. He became an official Mafia Boss at the age of fifteen. Well, technically he wasn't still the capital 'B' Boss, as while he was trained in combat, he wasn't trained yet in Mafia politics and such. And so he underwent another Training From Hell — aka paperwork.

He was a fifteen year old for goodness' sake. Yet instead of having fun, he was stuck here doing paperwork. He wasn't excited for the next school term seeing as he was also probably stuck with paperwork even during the term.

What was wrong with his life?

Then again, looking around at the people around him... Yuni was pretty young and Enma was still fourteen, both of them being younger than Tsuna. His Guardians were also the same age as him, with Onii-san, Mukuro and Hibari being older. It made Tsuna sad, seeing young people such as themselves stuck into this world of chaotic insanity.

"Oi Dame-Tsuna, what are you spacing out for?"

**_SMACK_ **

"Ouch, Reborn!" Tsuna cradled his poor head that was smacked by a Leon hammer. "And candidate?"

"Candidate. You know the latest news in the underworld, right?"

"Ah!"

And yes, Tsuna did know. He had heard of the whispers of the latest new target: a monster that the government couldn't hunt down. It was apparently the culprit for the destroyed moon — which honestly shocked Tsuna because he thought that Vongola would destroy that first — and was basically unkillable. Multiple hitmen and assassins went to confront the target (the only name it was known for) but all failed. It was too elusive — too skilled.

Yet new rumours sprouted, where they say that the target had settled in some school in Japan. Most hadn't confirmed the exact place, but Vongola had, with the help of CEDEF's informants. They had even confirmed the news that the Japanese government was willing to offer 10 billion yen for the assassination of the monster.

Ten. Billion. Yen.

Tsuna knew that being Vongola Decimo made him instantly rich with bank accounts even larger than that prize, but being formerly from the upper middle-class, he still viewed 10 billion yen as an impossibly huge amount.

The only problem now was that they had to assassinate the target to get the money. Tsuna wasn't willing to kill but he had heard rumours that the target would destroy Earth soon and he knew that he shouldn't hesitate to eliminate it. But he couldn't.

He couldn't kill, even if he's now in the Mafia (albeit reluctantly).

Tsuna looked at the baby (man) who could possibly kill that so-called monster. "Hey Reborn," Reborn gave him a glance. "Why don't you be the candidate? I mean you're the World's Greatest Hit — ouch!"

Reborn twirled the Leon hammer in his hand. "Dame-Tsuna, I am the greatest and therefore if I want to take a hit, then I'll take a hit. If I don't, then no."

Tsuna looked at his tutor from hell suspiciously but he knew that Reborn could be pretty stubborn and that once he wants something done, he will have that something done.

He sighed. "Fine. What do I need for candidates then?"

"The candidate must be ages 14-15, able to blend in, and skilled enough to assassinate the target."

"Eh?" Tsuna's eyes widened. "W-Wait, those requirements!"

"You're not as slow as I thought."

"Reborn, are you serious?! He —"

**_RING RING_ **

The sudden ringtone made him pause in his complaints. His eyes stared at the phone before him, as if it was like the ticking bomb his Storm Guardian had shown to him once. From the corner of his eye, he saw Reborn raising an eyebrow and quickly picked it up before the evil tutor had any ideas.

"Hello?"

_"Ah, Tsuna?"_

It was a familiar voice.

"Enma!"

Tsuna smiled. Enma was one of his closest friends. After the fiasco with Daemon Spade and the Arcobaleno Wars, the two bonded over their similar problems of being a young Don, and the respective craziness of their Famiglias.

The two also supported each other in taking over their roles as Decimo of their Famiglias. Both had difficulties and obstacles to overcome regarding that. For Tsuna, it was the fact that he was taking over the strongest Famiglia in the world. He was told by his dad, Reborn and Nono that he would not be supported by the other Famiglias if he does not prove himself. On the other hand, there was Enma, who was the head of a small Famiglia that recently revealed themselves. The Shimon Decimo was having a hard time stabilising their base due to lack of funds and the influx of mafioso wanting to join their Famiglia after their impressive display against Vongola.

"So why did you call?"

 _"Well, um..."_  Enma sounded hesistant. _"You know that new high profile target that everybody's been going on about?"_

"If by everybody you mean the entire Underworld, then yeah."

 _"Well... ImayhavegottenmyselfincludedandnowI'msupposedtoassassinateit."_  The words were said in one quick rush of breath.

"What?"

There was a pause before Enma started to talk, _"When we heard about the reward, Adel thought it would be nice because we need funds. But then only I seemed to blend in and had the age... I got forced."_

Silence.

_"T-Tsuna? Are you there?"_

"Uh yeah! It was just... I was just processing it. So... you're going to assassinate...?"

_"Yeah, I'm going to Japan tomorrow. Adel already booked the flight. I-I just thought of telling you becsuse Adel would, um, substitute for me during meetings so you won't be surprised."_

Tsuna rubbed the back of his neck, chuckling. "Yeah, I'll take note of that."

_"Okay. A-Anyway, I got to go. Wish me luck."_

The call ended and Tsuna slumped back down his chair. Enma was going to go and assassinate the target — who Tsuna was planning to send someone to. Tsuna sighed. Oh well, might as well forget about that ten billion. After all, Enma needed the money more than him. He might as well give —

**_SMACK_ **

"Ow, Reborn!" Tsuna glared at the baby hitman. "Why did you do that?!"

"Dame-Tsuna, a Boss does not give up. The Shimon may be Vongola's allies but that does not mean you will be lenient towards them. You will send a candidate who will assassinate the target, no buts."

"E-Eh?! But Enma —"

**_SMACK_ **

"Ouch!"

"I said no buts. Now go call your Rain Guardian."

"But I haven't even cho —"

**_SMACK_ **

"No buts. Vongola will get that ten billion."

In his heart, Tsuna deeply apologized to Takeshi for getting him involved in this mess.

* * *

Kozato Enma sighed as he ended the call. He still asked himswlf what did he get himself into, agreeing into going undercover to assassinate a yellow octopus. Thinking about it, it sounded completely ridiculous but what does that say about his life when it's real?

He remembered when the moon was destroyed. It was so out of nowhere that the world went into chaos. Conspiracy theories were everywhere and the most popular one was that the government had a hand into it. However, there was a different popular conspiracy in the underworld: the Vongola were responsible.

When he first heard that, he agreed. The Vongola were crazy enough to destroy the moon. So he just prayed for Tsuna to be able to find a way out of it. However, when Tsuna denied the fact that Vongola was responsible, Enma's curiosity peaked. Vongola had denied all relations to the moon's destruction.

Then the rumours started popping out.

Rumours about a monster... an alien... Then the Japanese government had released a bounty and the underworld went into a frenzy. Ten billion yen for an assassination. What made it even better was that even some famous hitmen and assassins had tried but failed. Everybody was itching to be the one to kill the target.

As that went on, Enma had hesitations. His Famiglia needed the money but he didn't know if they could get it. They didn't expect that their actions in the Inheritances Ceremony would garner them so much attention to the point that the influx of recruits was too much. He did have the inheritance of Shimon but that wasn't enough seeing as the Shimon was in hiding for years and therefore didn't had much time to establish businesses and sources of income.

So when they heard about the ten billion, Enma knew that they had to get it. But how? And so Adel pushed him into going as he was the most normal and trustworthy (he was the Boss after all). After all, they couldn't send someone like Shitt-P.

Enma merely sighed. It was for the Famiglia. He could do this.

* * *

Yamamoto Takeshi smiled as he faced his friend Tsuna, who looked unnerved as he tried to spit something out. He had been called by his friend to go to the office. Apparently he was needed for something.

Takeshi was just happy to help.

"S-So yeah. Um yeah. You, you just have to go to school, be a normal student and a-a-assassinate this one. It doesn't have a name as far as we know so most just call him target or the yellow octopus."

Takeshi looked at the open file on the table. It showed a yellow octopus wearing odd robes, as if it was some graduate. Hm, maybe he was one of those UMAs Gokudera kept yelling about? He had to ask his fellow Guardian about it. The octopus looked smart, maybe he was a graduate of some alien school?

"You must assassinate the target before the Shimon Decimo," Reborn said as he put down his coffee mug.

Takeshi kept his grin as he replied, "Before Enma? Oh, so it's like a new game?"

"Eh?" Tsuna looked hilarious with his gaping face. "No! Um, really Takeshi you don't have to do this."

"You do."

"Shut up Reborn!" Reborn pointed his gun at Tsuna and the latter immediately blanched.

On the other hand, Takeshi just watched the happenings with amusement. He knew it wasn't a game. He and his friends had gotten involved intovsomething they shouldn't had gotten into. But Tsuna was his friend — he was the only one to tried to stop him when he was filled with despair. He cared for Tsuna, and after those battles together, he cared for his fellow Guardians even if they didn't show their care much for one another.

He didn't want to abandon them. So he left the bat and took the sword.

"Ne, Tsuna. You need the money from this right?"

"Ah, well yeah." Tsuna rubbed the back of his neck before shaking his head frantically. "N-No! Um, well I planned to give it to Hibari-san for his Foundation but then Enma needed the money s-so yeah —!"

"Don't listen to him." Reborn jumped on Takeshi's shoulder. "Dame-Tsuna doesn't realise how this can benefit us."

"So this is important?"

"Yes."

"No!"

And Tsuna went back to arguing with Reborn. Takeshi looked at them while weighing in the pros and cons in his head. One, he could get back to Japan. Maybe even visit his dad. But then it was also a long-term thing and he didn't want to be far away from Tsuna and the others. But Reborn said it was useful for the Vongola...

"I'll do it."

Tsuna and Reborn looked at him, the former shocked and the latter smirking.

He wanted to help his friends — his Famiglia.

Even if it meant playing this dangerous new game.

**Notes for the Chapter:**

> So I'd had this idea for some time. Well, it was actually separate xovers, one with Enma as student of 3-E and one with Takeshi as a teacher. But then I couldn't choose which one to write so I decided: "Why not both?". An important note is: NO PAIRINGS other than canon pairings such as Irina/Karasuma.
> 
> Another note is that this ignores the last chapter with the Neo Primo thing and Tsuna accepts to be part of Vongola. Also, I messed with the timeline and made Tsuna older than Takeshi and Enma by a year (weird, I know). So Tsuna is 15 (Oct 16), Takeshi is wil turn 15 around the beginning (his bday is April 24 and school in Japan starts in April), and Enma is 14 (he'll turn 15 on June 16).
> 
> Lastly, Tsuna is close enough to his Guardians for him to call Gokudera and Yamamoto by their first names but not enough yet for Hibari. Gokudera still calls him Juudaime.
> 
> If you have any comments or feedback, please review! And thanks in advance!


	2. Target 2: Koro-sensei

**Summary for the Chapter:**

> In which Enma meets Yamamoto, the octopus gets named, and the two Mafioso get new friends.

**Notes for the Chapter:**

> DISCLAIMER: I do not own Katekyo Hitman Reborn and Assassination Classroom.

Being in a new school without his Guardians was uncomfortable.

Enma shuffled in his seat — he sat at the seat at the left side of the room (right side from teacher's perspective) — as he looked around his new classmates. It made him uncomfortable, being in a new environment. What was wrose was that unike before, when he transferred into Namimori, he didn't have his guardians with him. He lowered his head but kept his eyes on his new classmates for the rest of the semester. They hadn't seem to notice him yet, which made Enma a little relieved but also curious, seeing as he knew he was eye-catching with red hair in Japan.

But then, maybe his hair color wasn't odd. He thought of that as he watched the green-haired girl tie up the blue-haired boy's (?) hair. Were those hair colors natural? At least Enma knew his hair color came from his Italian blood. But blue and green hair... were they dyed? Was that allowed in this school? According to his information, Kunigigaoka had an excellent yet strict curriculum.

And strict it was indeed, he thought as he remembered climbing the mountain and seeing the shack they called a classroom. He failed his transfer exams, as expected, and got placed into Class 3-E, also known as the E-as-in-End Class, according to the whispers he heard.

Enma called back to the files he briefed himself before entering Kunugigaoka. His target was some yellow octopus alien, no name given. It was said to have supernatural abilities such as moving at Mach 20. It made him nervous. How was he going to go against someone who can move 20 times the speed of sound?! If he could use his Earth Flames, perhaps, but he had to take care because of omertà, the Mafia's code of silence. He didn't want the Vindice on his tail after all.

The target was also reported to have struck a deal with government leaders to teach Class 3-E of Kunugigaoka Junior High. Why this specific class, Enma wasn't sure, but he would like to find out.

"Oh, Enma!"

Enma immediately looked at the speaker who called him by his name despite never introducing himself to anybody. At the sight of the brightly smiling Rain Guardian of his friend Tsuna, Enma's eyes widened.

"Y-Yamamoto-san..!" Enma looked around and nobody seemed to be listening to them. "W-What are you doing here?"

Yamamoto plopped himself down at the seat at his right. "Tsuna sent me." His grin never faltered.

"W-Why?"

"Well, actually Reborn did. Something about octopus and beating it before you?" He leaned back at his seat before giving a thumbs up to Enma, who was just confused. "It's like a game! Me versus you."

The words finally processed in Enma's mind, which was previously filled with shock and confusion. "Wait... Vo — the clams want the money?" Despite them being in the corner, Enma couldn't risk eavesdroppers. Teenagers were curious, after all.

"Yup! For expansion, they said."

At those words, Enma slumped. He had competition for the prize money. And it was the 10th Generation Vongola Rain Guardian, who was praised (sort of) by Reborn himself (Rebon! Reborn of all people!) for having hitman instincts. So first, he had to find a way around Mach 20 and now he had to compete against a natural-born hitman who can throw baseballs that can smash concrete walls.

Enma took a deep breath before looking at Yamamoto in the eye, who seemed to sense the former's seriousness as his grin became a small smile. "I will not give up."

"That's the spirit!"

Natural-born hitman or not, Enma was still the Shimon Decimo and for his Famiglia, there was no such thing as giving up.

* * *

"If you're done, you may leave for the day."

Yamamoto Takeshi took a glance at his seatmate. Enma looked serious, albeit confused. He reminded Takeshi of Tsuna when the latter was faced with homework from school (not homework from Reborn — that drains every energy out of Tsuna's body). Takeshi himself twirled the pen in his hand. A poem ending in "tentacles"?

Takeshi took another glance at the strange octopus thing. He was curious as to what exactly was it (him? Her?). Was it some UMA that Gokudera loved talking about? Hmm... maybe it was related to Shitt P? Or maybe it was someone in a costume — like a school mascot!

Despite the weirdness, Takeshi also saw that their new teacher was skilled. According to the files (and its own self-introduction), it was responsible for the wrecked had also proven to have Mach 20 speed, as demonstrated in homeroom earlier, in which they tried to barrage him with bullets but it didn't work.

This game was harder than he thought. It made him wish that he could've brought Shigure Kintoki.

But the more challenging, the merrier after all!

_The rain comes, washing away sorrows_

_Leaving new ground for hope to sprout like tentacles._

"...ahaha, it looks like I really can't do poetry."

"I have a question."

Takeshi looked up to see that green-haired girl — Kayano-san, if he remembered correctly — raising her hand.

"Hm? What is it, Kayano?" Oh, it was Kayano, he was right. Score to Takeshi!

"I know the school year has already started but... what's your name? We really can't call our teacher "strange octopus thing he had to kill". "

"That's a bit long, yes... You know... I don't have a name! Why don't you think one for me? But after you finish your poem."

Kayano smiled and answered, "Okay!"

"Ehh, so he doesn't have a name? Isn't that weird, right Enma?"

The redhead twitched at Takeshi suddenly talking to him. "U-uh yeah. I-I guess that's why..." he trailed off.

Takeshi was going to ask him what he was going to say but a movement caught his attention. With sharp eyes, yet a grin never leaving his face, Takeshi saw the blue-haired boy — Nagisa — walk towards their teacher with a neutral expression. Behind his paper was an anti-sensei knife.

Nagisa was completely normal, except that his way of holding the paper was a clue that he could be hiding something behind it. The expressions of his classmates also gave away the plan. The octopus would probably be able to dsee through this and defend immediately.

Points for his poker face though.

And as expected, Nagisa attempted to stab the octopus and his arm was held by a tentacle, halting it from going further. However, Takeshi felt that something was off. He immediately looked around and saw the person two seats away from his right wearing a malicious grin as he held some sort of remote in his hands.

It was dangerous.

But before Takeshi could stand up, the person — he couldn't remember the name... Terasaka? — pressed the button and a loud bang came from the teacher's table.

"S-Shiota-san!"

"Nagisa!"

It was an explosion.

"Yeah!" Terasaka stood up, jumping for joy along with two other classmates. "We did it!"

"Sucks to be you!"

"I bet he wasn't expecting that!"

"Maa, maa, we weren't expecting it either."

The three turned around and looked at Takeshi, whose eyes narrowed as he glared at them, but the grin on his face never wavering. The three seemed to sense danger from him but were still high about their victory.

"You know, if you're not an expert, playing with firecrackers like that is dangerous."

Terasaka scoffed. "You dumb or something? That was a toy grenade with gunpowder and some of those special BB's."

Takeshi walked closer, until he was facing Terasaka. The tension in the room seemed to had doubled. And everybody was wary. "That was still dangerous. You could've killed Nagisa-san there."

"Pfft! It was just a small explosion." Terasaka backed away nervously and went down to Nagisa's body lying on the ground. "I'll cover his medical bills with the ten billion."

It was then that Takeshi felt something.

_Was that...?_

He looked up and felt shivers down his spine. It was as if Reborn was here in the flesh.

"Actually, I shed my skin once a month or so. I covered the bomb with it to absorb the explosion." Its tone held a dangerous warning. "I don't like having to do that."

* * *

"Ahh... The octo-wait, Koro-sensei is terrifying isn't he?"

As they went down the mountain, Enma nodded as he remembered the earlier events. He still felt like trembling in fear at the memory of the pitch black octopus. It was right at that moment that Enma recognized that the comdeic octopus teacher they had was indeed dangerous and had to be killed.

He gulped at the idea.

"I-It really was scary. I can't believe he would threaten us like that..."

"Ahaha, Tsuna and the others would be hard to take down if tried though!"

Enma sweat-dropped. Right. Koro-sensei, in some sense, technically threantened to attack Vongola and Shimon... If that ever happened, Enma would retreat with Tsuna (his fellow Sane Man) as it was sure to be a clusterfuck.

Trying to ignore the idea of Vongola's chaotic and destructive Guardians, his own chaotic Guardians and their octopus target slash teacher clashing, Enma changed the subject. "B-but the explosion was scarier. I-I was worried for Shiota-san..."

Yamamoto hummed as he put his hands at the back of his neck. "Yeah. Well, luckily Koro-sensei saved him! No injuries — not even a scratch! But you know, I think Nagisa was really impressive earlier. Even the octopus didn't deny it."

Enma remembered. Shiota was so calm and natural when he approached the octo — Koro-sensei. He suspected that the blue-haired boy may be some sort of natural hitman like a certain Rain Guardian.

"Oh? Yamamoto?"

Enma and Yamamoto looked back and saw two of their fellow classmates. It was Shiota and Tomohito. Enma remembered the latter getting along (aka being instant friends) with Yamamoto once they found out that the two of them played baseball. They hadn't played a game yet but Enma expected one sooner or later.

The two stopped in front of them, and it was then that they noticed Enma.

"Oh?" Tomohito looked at him. The attention unnerved the redhead. "You're the other transfer right? Ko... zato?"

Enma nodded. "Y-yes. Tomohito-san, right?"

"Yup! You can call me Sugino though. Oh, and this here's Shiota Nagisa."

The blue-haired boy bowed as he was mentioned. "Please call me Nagisa."

"A-Ah sure..? Um, Kozato Enma... But please, call me Enma." Enma, with a little reluctance, decided to add, "You were impressive earlier."

Shio — Nagisa flushed at the compliment. "It was nothing." And as if to change the subject, he added, "So, why did you decide to transfer to Kunigaoka?"

"Well... my guardian said I needed to learn and so she transferred me here." Enma then gave a rueful chuckle. "But I still failed the transfer exam."

"Aw man, I pity you." Tomo — Sugino said with a pat on Enma's shoulder.

Yamamoto grinned. "But hey, I also failed the test!"

"...that's not exactly something to be proud of."

It was the start of a friendship.

**Notes for the Chapter:**

> I was stuck as to what part of the beginning should I include. I was going to start with a Nagisa PoV, but I didn't want a verbatim recount of events in the first chapter. So I jist shifted between Yamamoto and Enma.
> 
> The first scene was set during the exact first day, when Nagisa met Kayano, before Karasuma introduced Koro-sensei. Then the next scene w/ Yamamoto was the first chapter in the manga (this is manga-based). I was actually goijg to have him stop it before Terasaka pushed the button, but the first chapter was a Character Establishing Moment for Terasaka, Nagisa, and Koro-sensei. I didn't go to the Koro-sensei threatens them because it would be exact verbatim w/ just Yamamoto.
> 
> Also, for now, Enma is sticking with Yamamoto abecause he knows the latter and making friends with people Yamamoto's kind of friends with. Once he interacts more with other 3E students, he will have his own social circle separate from Yamamoto.
> 
> As for Enma and Yamamoto's seats, look us Class 3-E seating arrangement. Enma sits to Ritsu's right and at his right side is Yamamoto (who has Karma right beside him).


End file.
